Individual variability of cognitive factors in second language (L2) grammar learning has long been the focus in the field of L2 acquisition. Most explored the issue by focusing on one factor like cognitive control, working memory, statistical learning (SL), or attention. Few investigated the topic by taking all these factors into consideration. However, different factors might interact and collaboratively contribute to the learning process. Examining the issue by considering all the factors might yield different results and facilitate our understanding of the mechanism subserving L2 grammar learning. Therefore, this study explored whether and how these factors predicted L2 grammar learning. A total of 34 college students completed a set of cognitive measurements on these cognitive factors, after which they were trained with artificial grammar over 5 consecutive days. Using multiple regression analysis and machine learning algorithms, we found that in the initial phase, SL was the more significant predictor, whereas in the intermediate and the last phases, cognitive control served as the more significant predictor. In other words, in the initial phase of L2 grammar learning, SL might play an important role, whereas in the intermediate and proficient phase, the updating component of cognitive control might play a more significant role. The findings provided empirical evidence to the neurocognitive account of grammar learning, shedding light on the mechanism of L2 grammar learning.

Verbs describe actions and changes in states, and are closely grounded in perceptual and motor experiences. Their core attributes align precisely with the embodied effect, which has increasingly attracted attention in research on verb processing and learning. To further clarify the influencing mechanisms and potential factors (verb concreteness, motor features, verb layer, depth of processing task and language status) of the embodied effect in verb processing and learning, a three-level meta-analysis with a random-effects model was performed on 37 studies (265 effect sizes and 12,357 participants) published in the past 15 years. The results revealed that there was an embodied effect in verb processing and learning, with a significant total effect size (Hedges’ g = 0.259, p < 0.005). Specifically, verb concreteness and verb layer moderated this effect. These findings suggest that future research should further explore the mechanisms and interactive influences of verb features and contextual information on the embodied effect. The findings further imply that language instruction may benefit from integrating embodied experiences with contextualized linguistic input to enhance verb learning and comprehension.

Positive valence bias refers to speakers responding faster to positive than negative information in L2 emotion words. Few researchers paid attention to the initial learning phase of L2 Chinese emotion idioms in which whether positive valence bias was acquired, based on the three-stage model of L2 vocabulary acquisition. Besides, whether the semantic information would modulate positive valence bias at the initial learning phase remained unclear. This study reports two experiments on speakers learning Chinese as a second language (CSL) to investigate positive valence bias in the initial learning phase of new Chinese emotion idioms and the modulation of semantic information on positive valence bias. Chinese as a second language speakers, who had acquired new Chinese emotion idioms and passed the test for learned Chinese idioms with a high accuracy rate before formal experiments, participated in Experiments 1 and 2. In Experiment 1, target materials were new Chinese idioms with positive and negative information. Positive valence bias at the initial learning phase of Chinese idioms was investigated with valence judgments. Experiment 2 used a semantic relatedness decision task further to explore the semantic effect on positive valence bias. The result in the first experiment showed that positive valence bias appeared in Chinese emotion idioms even at the initial learning phase of the acquisition. Meanwhile, semantic information of Chinese emotion idioms appeared to affect positive valence bias in the infant learning phase in Experiment 2. The findings revealed that semantic information would affect the performance of positive valence bias, suggesting that the semantic processing would automatically access the valence at the infant learning phase L2 Chinese emotion idioms. The research results provided evidence that positive valence bias would form in the infant learning phase of Chinese emotion idiom acquisition, based on the L2 vocabulary acquisition model.

Individual differences in statistical learning (SL) constitute an important cognitive mechanism that supports second language (L2) syntactic processing. However, existing research has primarily focused on adult populations, while potential differences across input modalities remain understudied. This study investigated the associations between SL and implicit L2 morphosyntactic processing among Chinese adolescent English learners, comparing results across visual and auditory modalities. Participants completed visual and auditory SL tasks, self-paced reading (SPR), self-paced listening (SPL), as well as working memory (WM) and attention tasks. L2 morphosyntactic processing ability was measured via grammatical sensitivity indicators extracted from SPR and SPL data. Mixed-effects analyses did not detect statistically reliable group-level grammaticality effects in either task, though SPR exhibited a descriptive pattern where ungrammatical sentences elicited longer reading times at the third word. Participants achieved higher accuracy on the visual SL task than the auditory one. In exploratory regression analyses, visual SL accuracy was found to positively predict grammatical sensitivity measured at Word 3 in SPR. Still, this association was not confirmed in a follow-up sensitivity analysis. No corresponding significant association was observed between auditory SL and SPL sensitivity, and neither working memory nor attention showed consistent independent contributions to the outcome. These findings extend individual-differences research on this topic to adolescent classroom L2 learners and underscore the potentially important role of visual regularity learning in online L2 reading processing.